Process for the obtainment of sheets of plastic material which are combined or backed



Patented June 2,1931

UNITED s'r 'rEs PATENT OFFICE man rarssnau, or um, rmcn I03 InOBTAIN'IENT- OF SEEMS OI PLLSTIO ILA-TRIAL WHICH ARE counmnn B BLCKED IoDrawing. Application fled Kay 85, 1928, Serial R0. and in France July 5,1927.

In the. current manufacture of plastic substances based'u nnitro-cellulose or acetylcellulose, it is t e usual practice to placetogether and'unite-two sheets, one of which is transparent and the otheropaque, for the obtainment of novel effects. r

For example, a thin sheet of artificial mother-of-pearl is backed by a.sheet of opaque materiahwhite or colored with black or various otherpigments. The said opaque sheet is visible through the transparentmaterial and-forms a background. The device co I of the two assembledsheets may be pl w. upon a strong and thick "plate of a less expensivesubstance which serves as a support, and the whole may be used for themanufacture of solid objects.

However, this method ,oifers certain disadvantages. The two thin sheetsare caused to adhere together by the hot pressing process, j after coatiili fi one or both sheets with a suitable solvent. erefore to produce asuccessful operation,- it is necessary to keep within the strict limitsof temperature and pressure,

since if the temperature becomes excessive, the substance will becomesoftened and will sink down, th'us changing its appearance, and if thetemperature is too low, the adhesion is imperfect i so In this lattercase, the two sheets will he quentl separate during theirhandling in themanu acture of articles. This separation is almost inevitable when thethin sheets are I softened by immersion in hot water, or in a suitableliquid, in order to mount them upon backin which cannot be spread out,such as a w shoe heel.

The process according to the invention will obviate all such defects,and by the use of sim- 7 in an effective manner and may in certain thebacking itself. Ehe said coating substance comprises differentconstituents whose proportions must ple and effective means,iIam'enabled to probe carefully calculated in order to obtain the desiredefiect.

For instance, if the operation is to be performed upon a sheet ofartificial mother-ofpearl or like substance having cellulose acetate asa base, the mixture should comprise:

" 1. A certain quantity of acetyl-cellulose which gives a certainstlfiness to the mixture andservesas binding material;

,2. A suitable amount of acolored powder, to or a'metalliccom ound, or'alake colored by anilin dyes, or a w 'te pigment and a solution of. ananilin: color, and in general, any suitable pigments; e

3.YA diluting liquid, which is sufliciently volatile to allow the rapiddrying of. the coating, and is so formed that in addition to the neutralsubstances serving exclusively as diluting bodies to afforl d thesuitable consistency of the coating material for the purpose, itcontains a solvent which is sufficiently active to'attack the surface ofthe coated sheet in order to obtain the adhesion, the said solvent beinghowever used in such quantity that it will not dissolve or buckle thesaid sheet.

A formula corresponding to the above indications is given as follows,-solely by way of example a Parts Pi ent I Et llactate 25 Met l-alcohol50 Ethy acetate 25 Cellulose acetate (plastic) 7 Obviously, each of thesolvents or diluting liquids may be replaced by other products such ascyclohexanol, methyl acetate, acetone, methyl-ethyl-acetone, or thelike, provided the mixture ofv such products forms acomplex substance of.a rather. volatile nature ,and slightly attacking the plasticsubstance, but not appreciably softening it. v For a coating uponaplastic substance having nitrocellulose as a base, instead of usingcellulose acetate it is obviously preferable to use celluloid" asabindin'g substance, as well as the proper liquids or solvents.

In practice the coating or point thus formed may applied by any usualprocess,

- has a flat or dull .aspect which may be unfavorable when the backedsheet is to be used alone for the manufacture of fancy articles, such aslam shades, or in general, all articles made of thin material. In suchcases it is an easy matter to ive to the whole a sufficient polish wherey it will exactly resemble the product obtained by the adhesioli of. ora two sheets as inthe known methods. this urposeI polish the coatedsheet in the poli ing press by the use of heat and pressure, accordingto the known polishing methods.

The aforesaid process has a further advantage from the fact that. itoffers multiple combinationswhich would be difiicult to produce with theknown methods.

In this manner I point by the stencil on the reverse side of the sheetto be backed, variegated patterns which may be as varied as desired, bythe combination of suitable colors, and can also shade oif several tonesto obtain shaded designs.

It will be easy to note the infinite diversity of the hues which can beobtained by my said method. On the contrary, in the known methods ofbacking by theuse of two pre-formed sheets, it is necessary to producethe colored sheets in large blocks which are then sliced, and this makesit very diflicult and expensive to obtain sheets of widely varying hues,due to the enormous number. of blocks which must be manufactured, andthe-diificulty of producing plastic blocks whose colors are the .samethroughoutthe several blocks.

I may further obtain novel as ects by applying successively two coats opaint having opposite tonality I obtain for instance a dead appearanceby first'applying a bright color, optionall transparent, and thencoverin it,'after rying, with a coat which is blac or neutral, or dark,which thus'forms a screen.

The aforesaid opaque black coat may contain lampblack, which isinsoluble.

The sheet thus prepared is adapted for adhesion to apiece of thickplastic substance, as readily as the sheet obtained by the adhesion oftwo thin sheets by' the known method. I obtain such adhesion in theusual manner, by coating the two sheets, thin and thick, with a suitablesolvent, and by placing them in the press, using heat and pressure forthe proper time.

Due to my new method, the sheets are more closely united than by thecurrent method in which the sheets must be perfectly dry. For thisspecial use I may infact cause the thin sheet to adhere to the thicksheet before the widely varying effects. v

For the use of my said new product in thecoatingon the first sheet hasentirely lost is solvent.

By the same method, I am further enabled to obtain novel effects bycrackling or by sets of. lines. For this purpose I first coat a coloredpaint'in which the amount of plastic material used as a binding is lessthan the amount of color. When drying, the layer, which lacks binding,will shrink and will form sets of cracks,-these varying according to therelative amounts of color and of plastic material dissolved.

After this crackled coat has dried, I may readily use the same method toapply a layer of black or dark paint, or one which has a favorablecolor, so as to form an opaque layer which appears in' the intersticesor cracks and thus affords a new artistic effect.

The said process is applicable not only to plastic substances of theartificial mother-ofpearl class, which aregiven by way of exampleasaffording the most interesting results, but also to all other plasticmaterial in thin sheets to which it is necessary, for any reason, togive a backing forming a screen, or which are to be placed'upon a thinsheet of a different color.

Also, according to the same principle, i. e. the use of a liquidconsisting of a voltatile mixture of such composition that it will onlyslightly attack the plastic substance I may '(1)- either cause to adhereto one face of the latter a sheet of paper having a desired color, andherein the adhesion is obtained by placing the whole in the press withthe use of heat and pressure, or (2) after the said paint or the likehas been applied, I may cause to adhere to the coated face, by means ofthe same liquid, a sheet of spongy paper or a piece of thin cloth suchas tarlatan, or wood in very thin sheets, or like strong and poroussubstances.

Such combinations afford a sheet of plastic material which due to thefact that it is rough on one side will be adaptedas well as anyveneering wood-for suitable adhesion 'to wood, for instance by asuitable carpenters glue.

The tarlatan or like fabric is preferably substituted for paper, due toits greater strength, when it is desired to obtain a very 1 substantialadhesion, as for instance for the production of thin bands of marquetry.

Due tothis modification, the plastic substances can be used for cabinetmaking and for marquetry, and by a. suitable combination" produce mostof colors, 8. given substance will pieces will adhere strongly together,and the backed by the fabric, adding if necessary a' thin sheet ofplastic material of the same kind, for protecting purposes.

As an interesting improvement, I may substitute for the said fabric ofnatural textile fibres, a fabric consisting of artificial silk. Thislatter is based preferably upon the use of nitro-cellulose if the fabricis to be applied to celluloid, or the use of acetate of cellulose ifapplied to a plastic substance containing acetyl-cellulose. vFor thisspecial purpose, susceptible of widely varying decorative uses, thefabric may consist of a non-loaded artificial silk, for a most efiectiveadhesion to the plastic substance.

I may further employ a colorless artificial fabric loaded with pearlessence. The fabric will sink into the plastic mass and thus becomesinvisible, leaving in view only the pearl essence, which affordsdecorative effects (variable at will) due to its changing or opalescenthues.

Due to the said use of theartificial fabric which is caused to absorbthe mixture accord ing to the invention and will sink into the plasticmass to form a single body, I may thus provide a sheet of valuable usewhich can be cut or punched, milled, or otherwise treated, with as greatfacility as ordinary plastic material.

Claims:

1. Process for the manufacture of sheets of plastic material which arecombined or backed, consisting in applying, on a sheet of plasticmaterial, a layer of a mixture adapted to attack but superficially thesaid sheet of plastic material and composed of a plasticmateriallsimilar to that of the said sheet dissolved in a volatilecompound comprising .a mixture of a so1v.ent of the said material and ofa volatile liquid unable to dissolve the said material.

2. Process for the manufacture of sheets of plastic material which arecombined or backed, consisting in applying, on a sheet of plasticmaterial, a la er of a mixture adapted to attack but super ciallythesaid sheet of of natural textile fibres,.

-to attack but material, and in subsequently subjecting said sheet thusprepared to the action of a polishing press.

3. Process for plastic material which are combined or backed,-consisting in applying, on a sheet of plastic material, a layer of amixture adapted to attack but superficially the said sheet of plasticmaterial and composed of plastic material similar to that of the saidsheet dissolved in a volatile compound comprising a mixture of a solventof the said material and of a volatile liquid unable to dissolve thesaid material, a colored filling substance being added to the firstnamed mixture.-

4. Process for the manufacture of sheets of plastic material which arecombined or backed, consisting in applying, on a sheet of plastic toattack but superficially the said sheet of plastic material and composedof a plastic material similar to that of'the said sheet dissolved ina-volatile compound comprising a mixture of a solvent of the saidmaterial and of a-volatile liquid unable 'to'dissolve the ,saidmaterial, and in applying on said layer material, a layer of a mixtureadapted the manufacture of sheets of."

before'drying a sheet of spongy and resistant material. q

5. Process for the manufacture of sheets of plastic material which arecombined'or backed, consisting in applying, on asheet of plasticmaterial, a layer of a mixture adapted superficially the said sheet ofplastic material and' composed of a plastic material similar to that ofthe said sheet 'dissolved in a volatile compound comprising a mixture ofa solvent of the said material and of a volatile liquid unable todissolve the said material, and in applying on said layer before drying,a layer of fabric.

(In testimony whereof I have hereunto aflixed my signature.

. JEAN PAIS SEAU,

plastic material and composed of a plastic 5 no v

